So as that first summer set in, we very quickly realised this place is dry, really, really dry. So dry that the ground cracks up. In fact, many of the trees we planted initially died because the cracking ground broke off their roots and hair roots, so they couldn’t absorb any moisture… So in such a dry climate you have to do two things (at least that I know of) and that is mulching and irrigating your plants. Over the years I have learnt that in this climate any plant, no matter how hardy it is, would have a good chance of dying if it isn’t irrigated. But of course, before you can provide any water to the plants, you have to collect it.
The early days
When we moved into our place in the spring, it had beautiful green lawns, many large native trees (mostly different Eucalyptus species) all along the fence and some vines that were irrigated to an extent. We found the property with a 13 500l tank off the house, and a 3 500l tank fed off the shed. Our old property in South Africa had a 5 000l tank that we used for rain water and grey water combined, so we thought we were in the pound seats – we had enough water to irrigate everything we had planted and more! Great was our surprise when the pumps ran dry early in the summer already.
So the first winter, we did a major upgrade – we added a 16 500l tank to the house and a 5 500l tank to the shed. Now we had enough water to irrigate everything we could possibly plant! But of course, we hadn’t been sitting still either – extensions to the vegetable garden and many more fruit trees were also added over that winter, and they also needed water… So that summer we again ran out of rainwater and had to resort to municipal water (read – expensive) to keep everything alive.
So during the second winter, we had another visit from my in-laws, and my father in law is an under-acknowledged maths, science and computer science genius. So, we did a few calculations, like roof surface area * average yearly rainfall and from that we got a lot of inspiration. We weren’t tapping nearly into the full capacity of what rainwater we could collect. So that winter we made major alterations to the gutters and downpipes (actually many of them became “cross-pipes”) and we installed a 24 000l tank connected to the house and an additional 10 000l tank coupled to the shed.
During the third winter we added another 24 000l tank to the house, quite a little distance away, but coupled it in parallel to the previous 24 000l tank, so that was done with very few plumbing alterations. OK, so NOW we have enough water!
Oh no, but what else did we do? In that same period we installed a massive 14m x 4m natural water swimming pool (more on that in another post), which needed to be filled with, guess what? Yes, rainwater! That happened in October, with not enough rain after that to re-fill the tanks properly. So there we were in another summer using water very sparingly, and very quickly falling back on municipal water. But at least the pool water didn’t cost us anything. Unfortunately though, we also brought in meters and meters of roll-on lawn for the back area around the pool, which had to be watered, otherwise it would just die in the harsh summer.
Overflows and underflows
Of course, with different sized tanks, the overflows are all on different levels. Not only is this a plumbing challenge, but also a water management nightmare. In the winter rainfall season we have to close off all the tanks and let them fill up from the largest to the smallest. In the dry summer season, we have to use them one at a time, from the smallest to the largest.
Get your valve settings wrong and you may miss collecting water in winter. Worse still, you may have overflows in summer, when you flow a larger tank into a smaller one – and that’s when you least want to waste water. So our water has to be managed very carefully.
But at least the fourth summer, after we had again planted about 40 more fruit trees in the winter before, we had almost enough water and almost came through the summer without using municipal water. Only in the last month of summer we used a bit of municipal water for the lawns.
I guess you can see where this story is going?
- In this dry area, you cannot collect enough rainwater. OK, not cost effectively… But you’ve got to do as much as you can afford (up to roof surface area * average rainfall capacity).
- Get and install the BIGGEST tanks right from the start.
- Try and keep all the tanks the same height at least.